Better inclusion of CSS file

Plugin.php

@@ -7,7 +7,7 @@ class Plugin extends Base
 {
     public function initialize()
     {
-        $this->template->hook->attach('template:layout:head', 'MittelTheme:layout/head');
+        $this->hook->on('template:layout:css', array('template' => 'plugins/MittelTheme/Template/css/main.css'));
         # $this->template->hook->attach('template:layout:top', 'MittelTheme:layout/top');
         # $this->template->setTemplateOverride('header', 'mitteltheme:layout/header');
     }

Template/layout/head.php

-<link rel="stylesheet" type="text/css" href="<?= $this->url->dir(); ?>plugins/MittelTheme/Template/css/main.css" media="all" />
\ No newline at end of file